Oil burner nozzle



Sept. 25, 1951 c. R. wALDRoN OIL BURNER NOZZLE Filed April 2l, 1948Patented Sept. 25, 1951 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to fuel and air mixing nozzles adapted for use informing a primary mixture to be burned in a blast of secondary air, suchnozzles being useful particularly in connection with low-pressure typeoil burners.

An object of the invention is to provide a better and a more quiet andeicient nozzle for use in connection with the formation of a primarymixture in loW pressure type oil burners.

Other and further objects of the invention will be apparent by referenceto the accompanying drawings of which there is one sheet, which, by wayof illustration, shows a preferred embodiment and the principles thereofand what I now consider to be the best mode in which I have contemplatedapplying these principles. Other embodiments of the invention embodyingthe same or equivalent principles may be used and structural changes maybe made as desired by those skilled in the art without departing fromthe present invention and the purview of the appended claims. I alsocontemplate that of the several different features of my invention,certain ones thereof may be advantageously employed in some applicationsseparate and apart from the remainder of the features.

In the drawing:

Fig. 1 is a fragmentary view illustrating an oil burning furnaceemploying a low-pressure type oil burner having a primary fuel and airmixing nozzle embracing the principles of the invention;

Fig. 2 is an enlarged longitudinal sectional View of a part of theprimary fuel and air mixing nozzle embraced in the structure disclosedby Fig. 1;

Fig. 3 is a cross sectional view through the fuel and air mixing nozzleillustrated by Fig. 1. Fig. 3 is taken substantially in the plane ofline 3-3 of Fig. 1; and

Fig. 4 is another cross sectional view through the nozzle illustrated bythe preceding figures, except that Fig. 4 is taken substantially in theplane of line 4 4 of Fig. 2 with the forward end of the inner tubularbody embraced in the nozzle shown in end elevation.

Referring particularly to Fig. 1, the numeral I indicates generally anoil burning furnace having a combustion chamber II which is surroundedby a wall I2 having an opening I3 formed therein for the reception of anair cone or nozzle member I4 through an orifice I6 in which a blast ofsecondary air is supplied to the combustion chamber II. Disposedoutwardly of the orifice I6 and concentrically relative thereto isaprimary fuel and air mixing nozzle I'I having an orifice I8 formedconcentrically Within the front end thereof and through which orifice ablast consisting of a primary mixture of fuel and air is discharged intothe combustion chamber Il concentrically with respect to the blast ofsecondary air supplied by the orifice I6. The nozzle I'I consists of anouter tubular body or member I9 having a front Wall ZI in which theorifice I8 previously referred to is formed.

The inner surface of the wall 2I is frusto-conical in formation, as isindicated at 22, the orifice I8 being formed at the smaller end of thesurface 22 which forms a knife edge around the periphery of the orificeI8.

Rearwardly of the surface 22, the interior of the body I9 is ofcylindrical formation as is indicated at 23, the cylindrical surface 23.being adapted to receive and to closely i'lt the exterior cylindricalsurface 24 of an inner tubular body 26. The forward end of the innertubular body 26 is provided with an annular frusto-conical seatindicated at 2l which is adapted to engage the surface 22 at the basethereof to provide within the front end of the outer body I9 a tipchamber 28 communicating with the orice I8.

Within the annular seat 2l the forward end of the inner body 26 isprovided with a planular annular surface indicated at 29 and from thecentral portion of which a conical tip indicated at 3| projects towardthe orice I8 in concentric relation thereto.

Beyond the annular seat 27 the inner body 26 has formed within theexterior cylindrical surface thereof a plurality of longitudinallydisposed channels or air and fuel mixing chambers indicated by thenumeral 32. The inner surfaces of the chambers or channels 32 are planesurfaces which extend in opposite directions toward the innercyiindricalpsurface 23 of the outer body I9 and at the ends of which areparalleled chanel side walls, the outer edges of which terminate in theexterior cylindrical surface 2li of the inner body 26. Between thevchannels 32 which are equally spaced about the circumference of theinner body 26, the exterior cylindrical surface of the inner body 2Bprovides a plurality of longitudinally disposed arcuate seats indicatedat 33 which engage and form a relatively fluid tight iit with the innercylindrical surface 23 of the outer body I9. The forward ends of thefuel and air mixing chambers 32 terminate at the seat 21 and areconnected with the tip chamber 28 across 3 the seat 21 by angularlydisposed passages 34 which are formed in the front end of the innertubular body 26.

The cross section of the passages 34 is not as great as the crosssection of the air and fuel mixing chambers or channels 32, so as toincrease the velocity of the primary fuel and air mixture to be formedin the chambers 32 as this mixture moves through the passages 34 fromthe chambers 32 to the tip chamber 28. The passages 34 are eccentricallyrelated to the end of the inner tubular body 26 and the tip chamber 28,the forward ends of the passages 34 terminating within the tip chamber28 within the annular surface 29 and in eccentric relation to the tipchamber 28. The rear ends of the passages 34 also terminate inthelforward ends ofthe chamber 32 in eccentric relation to the latterchambers and midway between the side walls thereof.

The inner body 26 is provided with a liquid fuel supply passage 38formed internally and toward the front end thereof, the passage 36 beingconnected to the chambers 32 intermediate the ends thereof by aplurality of radially disposed fuel supply ports 31. The outer ends ofthe ports 31 which terminate within the central portions of the channels32 are formed with relatively sharp edges so as to tend to divide and toatomize fuel which may be discharged from the ports 31 into the airwhich moves forwardly within the `channels 32.

Air ata relatively low pressure is adapted to be supplied to thechannels 32 by a conduit 38 which projects from the casing 38 of a lowpressure type oil burner which is provided with a pumping unit adaptedto supply fuel and air to the nozzle I1 'at approximately the samepressures. The oil burner also is provided with a fan forsupplyingsecondary air which is discharged into the combustion chamberII c through the orifice I8. For a morel complete description of an oilburner system of this type and the primary and secondary air, and thefuel pumping, metering and fanmechanism employed therein, reference may.be had to the co-pending applications for UnitedStates LettersPatent ofHoward E. Earl, Serial No. 2,881, led January l1, 19 18, for Oil BurnerSystem, now Patent ANo. 2,554,481, issued,` May 29,1951; Howard MEI.Earl, Serial No. 772,970,1,led VSeptember 9, 1947,4f7orMotorCompressonUnit, now PatentNo. 2,542,- 121; and Robert R.WitherelhuSer. No. 13,718, filed March 8, 1948, for Oil Burner PumpingUnit. d

The nozzle I1 'removably secured to the threaded end of the conduit 38by a coupling member 4I. Within the conduit 38 and also connected to theoil burner pumping unit referred to is a'noil supply conduit 42 whichsupplies oil to the 'cavity or passage 36 of the nozzle I1 through a'tube 43. The tube 43 is removably positioned at `its opposite endswithin the cavity 35 and the interior of the conduit 42. Surrounding thetube `43 is a spring 44 which `en-4 gages the 'adjacent ends -of theconduit 42 and the 'inner body 26, this spring being adapted toresiliently Yposition the inner body 28 within the outer body I8 withthe annular seat 21 in engagement with the front wall 2I of the outerbody IS.

The volume of the primary air supplied by the conduit 38 is severaltimes the volume of fuel supplied by the conduit 42, the ratio 'betweenthese quantities of fuel and air vbeing whatever ratio may be desired toproduce the primary mixture required.

From the conduit 38 the air supplied to the fuel and air mixing chambers32 moves forwardly within the mixing chambers toward the passages 34. Asthe air passes over the sharp outer ends of the ports 31 the air picksup and moves along the interior surfaces of the chambers 32 the quantityof fuel required for producing the primary mixture. The fuel and air soproportioned moves forwardly from the ports 31 at approximately thevelocity of the air supplied t the opposite ends of the chambers 32until the forward ends of these chambers are reached. In such regionsthe fuel and air mixture in the chambers 32 passes over the edgesdefining the rear extremities of the passages 34, thereby furthertending to divide and to atomize the fuel content of the mixture. Due tothis reduced cross section 'of the passages 34, the mixture V,sodescribed as moving forwardly within the chambers 32 increases invelocity in the passages 34 thereby tending to increase the atomizatonof the fuel and air mixture and to prevent a separation of the fuel fromthe air before the mxtureis discharged into the tip chamber 28. Owingto' the eccentric relation between the passages 34 and the chambers 32and 28, the mixture from the passages 34 is discharged into the tipchamber 28 in such manner as to rotate the fuel and air mixture withinthe tip chamber 28. From the tip chamber 28 the mixture isn dischargedover the knife edges of the orifice I8 in a blastV of fuel and air whichmoves forwardly through the orifice I6 into the combustion chamber II inconcentric relation to the secondary 'air also discharged in a blastthrough u*the* ori'ce IG. During the discharge of the oil and airmixture lfrom the orice I8, the cnical tip 3| which projects within theorifice y serves Athe purpose of preventing the formation of large dropsof oil in the nozzle during the operation thereof. The tip y3| whichprojects Ainto the orifice `I8 progressively increases f the velocity of'the 01'1 anu air mixture as it approaches passes over the knife edge ofthe orifice I8, thus 'causing a finer break-up of the fuel oil particlesas the mixture vis discharged from 'the orifice I8 and into and throughthe orifice )16.

1 It will lbe 'noted that the 'slope of the surface of the ltip 3| is-greater than the slope of the surface 22 forming the inside of thefront end N2'I of the body 'I8. Under Vsuch circumstances 'the 'crosssectional Varea o'f Athe tip chamber 28 therefore decreases 'frein thefront end of the body 25 to the knife edge orifice I8. Under s'uchcircumstances, Jth'e 'rotating body vo'f fluid forming the mixture inthe 'tip 'chamber 28 will increase in `velocity as vit approaches theknife edge orifice I8 and the apex of the tip 3 I.

The relation between the cross sectional varea V'of the air supply 'andmixing chambers 32, the 'eccentric passages 34, and the size and shapeof the Vtip 'chamber 28 is Vsuch 'that 'the velocity of the fluidinthese chambers as 'it moves toward the knife edge orifice `I'8'progressively increases.

Beyond the nozzle I1 'the V'primary air and fuel and the secondary Vairnmixture so formed 'may be ignited by electrodes indicated at 46 forforming la. suitable -fire within the combustion chamber I I.

When the oil burner 'controls are operated in such manner as todiscontinue the supply of fuel andair delivered to the nozzle I1 by theconduits 3^8 and 42, the conical tip 3| within the tip chamber 28 willtend to collect and to prevent the discharge from the orifice I8 of anylarge drops of fuel which otherwise might drip from the end of thenozzle H.

While I have illustrated and described a preferred embodiment of myinvention, it is understood that this is capable of modification, and Itherefore do not wish to be limited to the precise details set forth,but desire to avail myself of such changes and alterations as fallwithin the purview of the following claims.

I claim:

1. An oil burner nozzle comprising an outer tubular body having acircular sharp edged orifice formed coaxially therewith at the front endthereof, an inner tubular body within said outer body and having a frontend formed to provide an annular seat disposed in engagement with saidouter body and being spaced from said outer body at the front side ofsaid seat to provide a tip chamber communicating with said orifice, saidfront end of said inner tubular body having a conical tip disposedwithin said tip chamber and projecting toward said orificeconcentrically with respect thereto, said inner body on the side of saidannular seat remote from said tip chamber being formed to provide aplurality of seats engaging the interior of said outer body and aplurality of longitudinally disposed air supply and mixing chambersbetween said seats, one of said bodies being formed to provide aplurality of passages across said annular seat extending between saidair supply and mixing chambers and said tip chamber, said passages beingof less cross-sectional area than said air supply and mixing chambersand being formed in sloped relation to said air supply and mixingchambers and said tip chamber with the forward ends of said passagesterminating within said tip chamber and the rearward ends thereofterminating in said air supply and mixing chambers, said passages beingdisposed in directions eccentrically of said tip chamber so that saidpassage ends open into said tip chamber in a -direction for inducing therotation of fluid in said tip chamber, a plurality of spaced oil supplyports extending between the interior of said inner tubular body and saidair supply and mixing chambers and through which oil supply ports oil issupplied to said mixing chambers, the outer ends "of said ports formingrelatively sharp edges across said latter chambers facing the directionof flow of fluid in said latter chambers, said air supply and mixingchambers supplying air for mixture with the oil supplied through saidoil supply ports.

2. An oil burner nozzle comprising an outer tubular body having acircular sharp edged orice formed coaxially therewith at the front endthereof, an inner tubular body within said outer body and having a frontend formed to provide an annular seat disposed in engagement with saidouter body and being spaced from said outer body at the front side ofsaid seat to provide a tip chamber communicating with said orifice, saidinner body on the side of said annular seat remote from said tip chamberbeing formed to provide a plurality of seats engaging the interior ofsaid outer body and a plurality of longitudinally disposed air supplyand mixing chambers, said inner body being formed to provide a pluralityof passages across said annular seat between said air supply and mixingchambers and said tip chamber, said passages being of lesscross-sectional area than said air supply and mixing chambers and beingformed in sloped relation to said air supply and mixing chambers andsaid tip chamber with the forward ends of said passages terminating inequally spaced relation within said tip chamber and the rearward endsthereof terminating in said air supply and mixing chambers, said passageends opening into said tip chamber in a direction related to said tipchamber for inducing the rotation of fluid in said tip chamber, aplurality of spaced oil supply ports extending between the interior ofsaid inner tubular body and said air supply and miX- ing chambers andthrough which oil under pressure is supplied to said air supply .andmixing chambers, the outer ends of said ports forming relatively sharpedges across said latter chambers facing the direction of flow of fluidin said latter chambers, said air supply and mixing chambers supplyingair under pressure for mixture with the oil supplied through said oilsupply ports.

3. A nozzle according to claim 1 wherein the relation between the crosssectional area of the air supply and mixing chambers, said passages andthe size and shape of the tip chamber is such that the velocity of thefluid progressively increases as it moves toward the knife edge orifice.

CECYIL R. WAIDRON.

REFERENCES CITED The following references are of record in the nie ofthis patent:

UNITED STATES PATENTS Number Name Date 1,227,867 Young May 29, 19171,934,755 Williams Nov. 14, 1933 2,055,864 Harsch Sept. 29, 1936 A2,249,482 Macchi July 15, 1941 FOREIGN PATENTS Number Country Date82,573 Sweden June 28, 1932 87,106 Austria Jan. 25, 1922

